Question

Place the following elements in order of decreasing atomic radius. Cd Rb Xe Rb > Cd> Xe Xe> Cd> Rb Cd > Rb>Xe Rb> Xe> Cd Xe> Rb> Cd

Answer 1

Atomic Radius:

Atomic radius is the distance between the nucleus and outermost atomic orbital.

In the periodic table, while moving Top to bottom number of shells increases so the atomic radius also increases in the top to bottom.

While moving left to right electrons are adding in the same shell. On the same time left to right effective nuclear charge increased. So in the periodic table left to right atomic radius will decrease.

Rb, Cd, Xe:

The given three elements are fifth-period elements. Rb is the first element of the fifth period (largest radius in the fifth period) Cd is the 12th element of the fifth period and Xe is the last element of the period( largest element in the fifth.period).

Correct Answer; Rb,$>$ Cd,$>$ Xe